Pearlite or spheroidite

If steel alloy having either pearlitic or bainitic microstructures is heated to, and left at, a temperature below the eutectoid for a sufficiently long period of time (e.g.24hr), spheroidite will form. However from the phase diagram we know for eutectoid composition liquid, if we give it enough time pearlite will form (all phases in the diagram assume long transformation time). So what will we get, spheroidite or pearlite, if we cool very slowly?